Spark-plug tester.



A. P. JACKSON.

SPARK PLUG TESTER.

APPLICATION FlLtD MAR. 22, Hi5. 1,182,090. nf May 9,1916. 7

2 SHEETS-SHEET I.

8M vemfoz A P. MIKS'JY.

S Ah'K PLUG {ESTER A UCAHQN FILED MAR. :3. W

1,182 090. Pair-11ml Many J, 1916.

2 SHEETS SHEET 2.

17.126704 @z/z a fie UNITED STATES PATENT oFricE.

ALBERT P, JACKSON, OF DENVER. COLORADO, ASSIGNOR OF ONE-HALF TO LESTER A. SIEGFRIED, OF DENVER, COLORADO.

Application filed March 22, 1915.

0 all whom it may concern Be it known that I, ALnnnT P. JACKSON, a citizen of the. United States, residing in the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in SparlePlug Testers; and I do declare the following to be a full, clear, and exact description of the in vention, such as will enable others skilled in the art to which it appertains to make and use the same, referen e being had to the accompanying drawings, and to the characters of reference marked thereon, which form a part of this specification.

My invention relates to improvements in testers for the spark plugs of internal combustion engines.

It has been determined by actual demon stration that spark plugs which will spark or are properly between the electrodes in the open air or under.atmospheric pressure only, will not, properly perform their function when in use, owing to the fact that the pres sure within the engine cylinders in which they are employed, retards sparking. Hence, a higher degree of perfection is required in order that a plug of this character may properly perform its function within the cylinder of the engine than is necessary when the sparking or arcing function is performed under different conditions or under atmospheric pressure only. And it is for this reason that engine diflieulties arise, due to failure. of explosions in the cylinders of these engines tluuigli the spark plugs when subjected to the usual open air test, appear perfect.

The object of my present invention is to test these plugs with their electrodes under pressure equal to that within the cylinders where the plugs are to be employed. In order to do this, 1 provide a chamber either composed mainly of glass or other suitable sutliciently transparent material, or having a glass-covered opening through which the sparking of the plug may be observed, and connect this chamber with an air pump apparatus in such a manner that the air pressure within the chamber may be raised to the required degree, or to the maximum degree existing within the cylinders of r-xplosire eniines when in use. This chamber is so ar ranged that when the electrode extremity of any spark plug is inserted therein. the spark plug may be mounted in such a manner that Specification of Letters Patent.

Patented May 9, 1916.

Serial N 0. 16,244.

an air tight connection shall be maintained between it and the spark plug opening in the chamber. I then connect the spark plug in a suitable circuit of such character that when the circuit is closed, the plug will re spond thereto by producing a spark or are between its electrodes in case it is in proper condition for use in the engine cylinder.

In additon to the provision for compressing the air within the spark plug chamber as just explained, I also connect with this chamber a pressure gage arranged in such a manner that the pressure within the chamher is clearly indicated to the operator while operating the air pump or bringing the pressure up to the required degree within the chamber in any other suitable manner.

In my improvement, and as a part of the complete apparatus, I employ a suitable induction coil, the primary wires of which are adapted to be connected with a suitable num ber of battery cells for the purpose.

This apparatus may also be employed for testing the spark coils employed in connection with explosive engines.

Having briefly outlined my improved construction, I will proceed to describe the same in detail, reference being made to the accompanying drawing in which is illustrated an embodiment thereof.

In this drawing,-Figure 1 is a top plan view of my improved spark plug tester showing the complete apparatus. Fig. 2 is a fragmentary sectional view in detail illustrating a modified form of construction for connecting the spark plug in the circuit. This is a section taken online 22, Fig. 1. Fig. 3 is a section taken on the line 33, Fig. 1. Fig. 4 is a section taken at right angles to Fig. 3, and is indicated by the line 44, Fig. l.

The same reference characters indicate the same parts in all the views.

Let the numeral 5 designate a chamber, whichgas illustrated in the. drawing, consists of a cylindrical glass member 6 which is mounted between two metal members 7 and 8 and secured by clamping screws or bolts 9, which are passed through the member T and threaded into the member The member 7 consists of a disk 10 having a flange 12 surrounding one extremity of the glass cylinder, the space between the flange and the cylinder being closed by a ring 13 which is tightly secured therein. Between screws,- as heretofore explained, a tight oint' may be formed between the extremities .of the cylinder and the two metal members.

The metal member 8 forms the main body or framework for supporting the cylinder,

and for this purpose it is provided with a base flange 17 which engages a base 18 upon. which all of the apparatus may be mounted. This member. 8 is secured to the baseby means of screws or other suitable fastening devices 19 which are passed through the flange 17 and threaded into the base. a

This member 8 is further provided with a relatively large opening 20 for receiving the electrode extremity 21 of the spark plug 22. Surrounding this opening on the outside of the member 8, or the side remote from the glass cylinder, is a gasket 23 which engages a shoulder 24 formed on the spark plug, which, by means of suitable mecha nism, is forced against this gasket with sufficient power to form an air tight joint around the spark plug opening in the metal member. As illustrated in'the drawing, a

clamping member 25 is slidably mounted on two bolts 26, whose inner extremities are anchored in the metal member 8 on opposite sides of the opening 20. The outer extremities of these bolts or shanks arethreaded to receive washers 27 and wing nuts 28 which are threaded thereon and screwed against.

force for the purpose.

The clamping member'25 is preferably hingedly or pivotally connected with one of the bolts 19 (see dotted lines in Fig. 3) while its opposite extremity is provided with a recess 30 adapted to engage the other bolt 19 when the clamping member is in position for use.

By virtue of this construction, the spark plug may be readily clamped in place and as readily released.

The metal member 8 is further provided with a small passage 31, one extremity of which communicates with the chamber of the cylinder 6 while its opposite extremity communicates with an opening 32 formed in the threaded nipple 33 of a pressure gage This gage is of usual construction, its

face being properly graduated to clearly indicate the degree of pressure within the cyl-' which communicates at one extremity with.

the cylinder 6 as shown at 36 and at its opposite extremity with the cylinder 37 of an air pump as shown at 38. This pump is a flanged base 39 perforated to receive screws orother suitablefastening devices 40 which are passed through the flange of the cylinder of usual construction, beingv provided with I r and threaded into the base 18 upon which the apparatus is supported as heretofore explained. 'Between the cylinderof the air pump and the passage 35 is arranged a conduit 41 preferably composed of metal, whereby the pump cylinder and the metal part 8 are rigidly connected to form a perfectly stable structure.

Assuming that a spark plug 22 is inplace as shown in Figs. 1 and 4, and properly adjusted as heretofore explained in order to form a tight joint around the opening 20, 5

may be compressed to a degree correspond.

ing with the maximum pressure (if desired) attained within the cylinders of explosive engines at the time that the sparking or arcing of plugs of this character is neces-' sary. This degree of pressure will be indi-, cated on the pressure gage, as will be 'readily understood. When the apparatus is in use for spark plug testing purposes, the spark plug is located within the secondary circuit ofan induction coil or transformer 42 whose primary conductors 43 and 44 are connected with conductor members 45 an '46 of a number of battery cells 47. In the drawing, I have illustrated three dry cells df ordinary stock construction and which are therefore readily obtainable wherever electrical supplies are kept. In placing the apparatus upon the market, it is not my intention to apply these cells and for this reason I have distinguished the conductors 45 and 46 which are supposed to go with the cells from the conductors 43 and 44, in referring to the primary circuit. The wires 43 and 44 of this primary circuit are respectively connected with contacts of the induction coil or transformer, as shown at 48 and 49, this connection being made so far as the con'duit 44 is concerned, through the medium of an auxiliary conductor 50, which is connected as shown at 52 with a push but ton 51 with which the conductor 44 is also connected as shown at 53. This push butthe primary memb ton is employed for closing the circuit when it is desired to operate the apparatus for testing purposes.

The induced current from the induction coil is carried from the latter through a conductor 54 to a spring 55, which is secured at one extremity to the base 18 as shown at 56, while its opposite extremity merges into a member 57, which when the spark plug is in place, is arranged to bear against the outer extremity thereof (see full lines in Fig. 3). When the spring 15 in this condition, the spark plug is connected in the circuit for testing urposes; since the induced current is delivered to. the plug through the medium of the spring 55, and passes thence through the metal part 8 of the structure and thence by way of a conductor 58 to the conductor 43 of the primary circuit, this connection being made at the point 59.

i a When it is desired to test an induction or spark coil 60 (see dotted lines in Ih'g. 1) the primary member of this coil may be connected with the primary circuit through'the medium of conductors 61 and 62 and auxiliary conductors 63 and 64, the latter being connected with the primary member of the coil 60 as shown at 65 and 66. The conductors 61 and 62 are designated separately from those designated 63 and 64 since it is not intended to supply the conductors 63 and 64 with the instrument. The conductors 61 and 62, however, will be connected with binding posts 67 and 68 carried by the instrument, so that the conductors 63 and 64, which are simply primary terminals of er of the induction coil, may be readily connected with these binding posts. T e induced circuit is passed through the induction coil 60 by way of an auxiliary conductor 69 connected at one extremity with the secondary member of thecoil as shown at 70 and at the other extremity with the binding post 71 with which the member 54 of the secondary circuit is also connected.

Of course, while testing the induction coil, the circuit will be passed through the spark plug testing apparatus.

In the form of construction shown in Fig. 2, the body of the induction coil or transformer 42 is provided with contacts 72 and 73 which, when the coil is set within a casing 74, engage cooperating spring actuated contacts 75 and 76 with which the conductors 43 and 50 of the primary circuit are respectively connected. Furthermore, the induction coil or transformer structure is also provided with a contact 77 which engages a coiiperating spring-actuated contact 78 'with which the conductor 54 of the secondary circuit may be connected. In order that in introducing the coil or transformer 42 into the casing it may be properly placed to bring the difierent sets of cotiperating contacts into engagement, the casing is provided with a notch or recess 79 adapted to be engaged by a member 80 carried by the element 42. By virtue of this construction and arrangement, no mistake can be made in properly placing the element 42 in order that it may be operatively arranged.

From the foregoing description, the use and operation of my improved spark plug testing apparatus will be readily understood. When it is desired to test a spark plug 22, for instance, (see Fig. 4), the electrode extremity of the plug is introduced into the compression chamber through the opening 20, the gasket 23 being located between the shoulder 24 and the member 8. The clamping member 25 is then thrown into engagement with the spark plug (see Figs. 1 and 4),

after which the thumb nuts 28 are tightened sufficiently for the purpose. The air pump, whose piston stem 81 is equipped with a handle 82 for the purpose, will then be operated until the pressure gage indicates that the air within the chamber of the cylinder 6 has been raised to the proper degree of compression. The spring 55 is then connected with the spark plug by placing the member 57 thereof in engagement with the outer exposed extremity of the plug. Then, by pressing the push button 51, the circuit will be closed through the spark plug, and if the plug is in proper condition for use in an engine cylinder, the proper sparking or arcing result between the electrodes will be observed.

Having thus described my invention, what I claim is,

1. Aspark plug tester comprising a compres sion chamber open to receive spark plugs of varying sizes, a gasket surrounding the opening in the chamber and adapted to be engaged by said plug, means for clamping the plug in place against the gasket to form an air tight joint, means for compressing the air in said chamber, and a circuit in which the spark plug is located.

2. In a spark plug tester, the combination of a compression chamber including an openended cylinder, metal members applied to the opposite extremities of said cylinder and secured together to form tight joints at the extremities of the cylinder, one metal member closing the adjacent cylinder end while the other is provided with an opening to receive spark plugs of varying sizes, a gasket surrounding said opening and adapted to be engaged by the spark plug, and means for clamping the spark plug in place.

3. In a spark plug tester, the combination of a compression chamber including an openended cylinder, metal members applied to the opposite extremities of said cylinder andsccured together to form tight joints at the extremities of the cylinder, one metal member closing the adjacent cylinder end while the other is provided With an opening to receive spark plugs of varying sizes, a gasket surrounding said opening and adapted to be engaged by the spark plug, means for clamping the spark plug in place, and means for compressing the air within the chamber.

4. In a spark plug tester, the combination of a compression chamber including an openended cylinder, metal members applied to the opposite extremities of said cylinder, and secured together to form tight joints at the extremities of the cylinder, one metal member closing the adjacent cylinder end while the other is provided with an opening to receive spark plugs of varying sizes, a gasket surrounding said openingand ada ted to be engaged by the spark plug, means or clamping the spark plug in place, means for compressing the air within the chamber, and a pressure gage in communication with the chamber.

5. The combination of a chamber comprising a cylinder having a transparent portion, caps applied to the opposite extremities of the c linder, gaskets located between the cylin er extremities and the caps, means for connecting and tightening the caps, one of the latter having an opening to receive spark plugs of varying sizes, a relatively large gasket surroundin said opening and adapted to be engaged by the spark plug, means for clamping the plug in place, an electric circuit in which the spark plug to be tested is located, and means for closing the circuit through said plug.

6. A spark plug tester comprising a compression chamber open to receive spark plugs of varying sizes, means for clamping a spark plug in place, means for sealing the joint between the spark plug and the open extremity of said chamber, an air pump in communication with the chamber, and a pressure gage also in communication with the chamber.

7. In a spark plug tester, the combination of a compression chamber open to receive spark plugs of varying sizes, means for securing the spark plugs in place, means for compressing the air within said chamber, a pressure gage connected with the chamber, an induction coil or transformer, a battery, and an operative connection between the battery, the induction coil and spark plug for closing the circuit through the latter, substantially as described.

8. In a spark plug tester, the combination of a compression chamber open at one extremity to receive the spark plug to be tested, means for clamping the spark plug in place, means for sealing the joint between the spark plug and the open extremity of the chamber, means for compressing the air within the chamber, a pressure gage connected with the chamber, a primary circuit, an induction coil or transformer connected in operative relation with the primary circuit, and means for closing the secondary circuit through the spark plug, substantially as described. i

9. A spark plug tester comprising a compression chamber open to receive spark plugs of varying sizes, a gasket surrounding the opening in the chamber and adapted to be engaged by said plug, means for clamping the plug in place against the gasket to form an air tight joint, and a circuit in which the spark plug is located.

In testimony whereof I affix in presence of two witnesses.

ALBERT P. JACKSON.

my signature Witnesses:

A. J. OBRIEN, A. EBERT OBRIEN. 

